298 Mr. Ernest Ewart Unwin on the 
way, serve to keep the egg in place, and thus insure the 
emergence of the larva into the open air instead of into 
the more or less fluid mass in which the egg is situated. 
The larva issues from the egg just above the base of these 
appendages.” 
The egg of Drosophila funebris has four of these append- 
ages; they are generally stretched out over the surface of 
the pulp, and would certainly keep the egg from sinking. 
Another probable function of the filaments is to supply 
the egg with air. The exceeding whiteness of both egg 
and filament led me to suspect the presence of air. The 
egg-shell or chorion shows an hexagonal pattern on the 
surface, and under the high power of the microscope 
exhibits a spongy or granulated structure. It is in this 
layer that the air is contained. The filaments are con- 
tinuous with the substance of this layer, having a spongy 
core surrounded by a compact wall. Air is also present in 
the spongy core of the filaments. The eggs of many 
Hemiptera have a similar contrivance. Some have a pair, 
others a greater number of filaments at the upper end 
of the egg. Korschelt * considers these filaments to be 
respiratory in function. The eggs of aquatic Hemiptera, 
such as Nepa or Ranatra, that are furnished with these 
filaments, are deposited in the stems of water plants, and 
the filaments protrude from the stem into the water. In 
the case of Capsid bugs the filaments project into the air. 
The eggs of Drosophila are inserted into fermenting fruit 
where respiration is impossible or very difficult; the fila- 
ments projecting upwards or lying on the surface of the 
mass will, however, be able to act as respiratory organs. 
The eggs after two or three days hatch into minute larve. 
Drosophila and Fermentation.—Drosophila flies feed upon 
fermenting fruit-masses. In consequence of this their 
bodies readily harbour bacteria and other germs, and the 
flies often act as infection-carriers from one fruit-mass to 
another. 
In his paper on “The Sorbose Bacterium” t Bertrand 
gives evidence that supports this view. He noticed that 
Drosophila flies were attracted to a dish containing fer- 
menting rowanberry-juice, and that they laid their eggs in 
the thick scum that had formed on the surface. After the 
visit of the flies the character of the scum changed, and at 
the same time a change took place in the liquid. The 
* Korschelt (1886). + Bertrand (1904). 
